Phthalic acid ester-modified organopolysiloxane and method for its preparation

ABSTRACT

There is disclosed a novel phthalic acid ester-modified organopolysiloxane having the general formula ##STR1## where in R 1  is a monovalent hydrocarbon group, R 2  is a group R 1  or a group with the formula ##STR2## with the proviso that at least one of the groups R 2  in each molecule is the group with the formula ##STR3## in which R 3  is an alkyl group, R 4  is an alkylene group, and m is a positive integer. 
     The organosiloxane is useful as a co-reactant in the preparation of organic resins such as polyesters, polyamides and polyimides.

The present invention relates both to a novel organopolysiloxane as wellas to a method for its preparation. More specifically, the presentinvention relates to a novel organopolysiloxane which contains thephthalic acid ester group in the molecule, and also to a method for itspreparation.

BACKGROUND OF THE INVENTION

Organopolysiloxanes have a very broad range of characteristics, forexample, occurring as oils, rubbers, and solid resins, by virtue ofvariations in the composition of their basic structure, dimensions,configuration, species of pendant group, and molecular weight, amongothers. This, coupled with their characteristic heat resistance, coldresistance, oxidation stability, ageing resistance, releaseability, andwater resistance, etc., has resulted in their use in a wide variety ofindustrial spheres, for example, in the textile industry, for releasepaper, in the electric/electronics industries, in construction, and aspaint additives. However, organopolysiloxanes having the phthalic acidester group in the molecule and a method for their preparation have bothheretofore been unknown.

SUMMARY OF THE INVENTION

The present invention introduces a useful and novel organopolysiloxanewhich contains the phthalic acid ester group in the molecule, and alsointroduces an efficient method for its preparation.

The present invention therefore relates to a phthalic acidester-modified organopolysiloxane characterized by the formula ##STR4##wherein R¹ is a monovalent hydrocarbon group, R² is R¹ or a group withthe formula ##STR5## with the proviso that at least one of the groups R²in each molecule is the group ##STR6## in which R³ is an alkyl group, R⁴is an alkylene group, and m is a positive integer

The present invention further relates to a method for preparing theabove described organopolysiloxane comprising reacting, in the presenceof a platinum-type catalyst, an organohydrogenpolysiloxane having theformula ##STR7## wherein R¹ is a monovalent hydrocarbon group, R⁵ isgroup R¹ or a hydrogen atom, with the proviso that at least one of thegroups R⁵ in each molecule is a hydrogen atom, and m is a positiveinteger, with a phthalic acid ester compound having the formula ##STR8##in which R³ is an alkyl group and R⁶ is an alkenyl group.

DETAILED DESCRIPTION OF THE INVENTION

The phthalic acid ester-modified organopolysiloxane of the presentinvention has the formula ##STR9## wherein R¹ is a monovalenthydrocarbon group, R² is a group R¹ or a group with the formula##STR10## with the proviso that at least one of the groups R² in eachmolecule is the group with the formula ##STR11## R³ is an alkyl group,R⁴ is an alkylene group, and m is a positive integer.

R¹ in the above formula is a monovalent hydrocarbon group, asexemplified by alkyl groups such as methyl, ethyl, propyl, and octyl;substituted alkyl groups, such as 2-phenylethyl, 2-phenylpropyl and3,3,3-trifluoropropyl; aryl groups, such as phenyl and tolyl; andsubstituted aryl groups. R² comprises a group R¹ or a group with theformula ##STR12## in which R³ and R⁴ have their previously definedmeanings.

The location at which the phthalic acid ester group is bonded is notspecifically restricted, and it may be an ortho-phthalic acid ester, ameta-phthalic acid ester or a para-phthalic acid ester. R³ is an alkylgroup, as exemplified by methyl, ethyl, propyl and octyl. R⁴ is analkylene group, and examples in this regard are

--CH₂ CH₂ --

--CH₂ CH₂ CH₂ --

--CH(CH₃)CH₂ --

--(CH₂)₄ -- and

--(CH₂)₅ --

In the above formula for the phthalic acid ester-modifiedorganopolysiloxane, m is a positive integer, preferably having a valueof 1 to 5,000.

The following are provided as concrete examples of the phthalic acidester-modified organopolysiloxane of the present invention. ##STR13##

The present invention's method for the preparation of the phthalic acidester-modified organopolysiloxane follows. Theorganohydrogenpolysiloxane used as the initial starting material in thepresent invention's method has the formula ##STR14## In this formula, R¹is a monovalent hydrocarbon group, which is exemplified as above. R⁵ isa group R¹ or a hydrogen atom, and at least one group R⁵ in eachmolecule is a hydrogen atom. Again, m is a positive integer, preferablywith a value of 1 to 5,000.

The phthalic acid ester compound used in conjunction with the aboveorganohydrogenpolysiloxane in the method of the present invention hasthe formula ##STR15## wherein R³ is an alkyl group and R⁶ is an alkenylgroup.

R³ in the above formula is an alkyl group, and this group is exemplifiedas above. R⁶ is an alkenyl group, for which the following are exemplary:

--CH═CH₂

--CH₂ CH═CH₂

--C(CH₃)═CH₂

--(CH₂)₂ CH═CH₂

--(CH₂)₃ CH═CH₂

The phthalic acid ester compound is readily synthesized by a "Williamsonether synthesis reaction" between an alkenyl halide and anhydroxyphthalic acid, and by submitting the product to an esterificationreaction.

The platinum-type catalyst used in the method of the present inventionfunctions to promote the addition reaction between the SiH group in theorganohydrogenpolysiloxane and the alkenyl group in the phthalic acidester compound.

Examples of these platinum-type catalysts are chloroplatinic acid,alcohol-modified chloroplatinic acid, chloroplatinic acid/olefincomplexes, complexes of chloroplatinic acid and vinyl group-containingorganopolysiloxanes, platinum black, catalysts in which solid platinumis supported on a carrier such as silica or alumina, as well asrhodium/olefin complexes.

The method of the present invention consists of reacting theabove-mentioned organohydrogenpolysiloxane and phthalic acid estercompound in the prsence of the platinum-type catalyst. Theorganohydrogenpolysiloxane and phthalic acid ester compound should beused in proportions such that the molar ratio of siloxane SiH to alkenylgroups in the phthalic acid ester compound preferably falls within therange of 1:1 to 1:10 and more preferably 1:1 to 1:3.

The reaction environment is not specifically restricted, and thereaction can be run in the presense or absense of solvent, in the air orunder an inert gas, and under ambient pressure, elevated pressures, orreduced pressures.

Various reaction solvents can be used here, with the proviso that theydo not inhibit the addition reaction between theoganohydrogenpolysiloxane and the phthalic acid ester compound. Concreteexamples include aromatic hydrocarbon solvents, such as benzene, tolueneand xylene; aliphatic hydrocarbon solvents, such as hexane and heptane;ether solvents, such as tetrahydrofuran and diethyl ether; alcoholsolvents, such as methanol, ethanol, propanol and butanol; ketonesolvents such as acetone and methyl ethyl ketone; ester solvents, suchas ethyl acetate and butyl acetate; halogenated hydrocarbon solventssuch as carbon tetrachloride, tetrachloroethane and chloroform;dimethylformamide; and dimethyl sulfoxide.

The reaction can be run at room temperature, but in general it isadvantageous to run the reaction at 50 to 200 degrees Centigrade.

The phthalic acid ester-modified organopolysiloxane of the presentinvention, by virtue of its content of 2 ester functional groups, can beadded as a copolyermization component in the preparation of organicresins such as, for example, polyesters, polyamides and polyimides. Theparticular characteristics of organopolysiloxanes, such ashydrophobicity, water resistance, ageing resistance, etc., will thuspresumably be imparted to the organic resin.

EXAMPLES

The present invention is illustrated by the following examples. In theexamples, %=weight%, Me=methyl and properties were measured at 25degrees Centigrade unless specified otherwise. Furthermore, the solventand reagents were dried until the water fraction could not be detected.

(REFERENCE) EXAMPLE 1

137.3 mmol (25 g) 5-hydroxyisophthalic acid, 164.71 mmol (19.9 g) allylbromide, 27 g potassium hydroxide, 750 mL ethanol and 150 mL water werecharged to a stirrer-equipped four-neck flask. After heating underreflux for 10 hours, 120 mL 10% aqueous potassium hydroxide was added.After hydrolysis by heating under reflux for 2 hours, neutralization wascarried out by the addition of dilute (10%) hydrochloric acid. Thesolvent was removed on an evaporator, followed by extraction of theproduct with diethyl ether and distillation of the diethyl ether toafford crude crystals. These were recrystallized from water/ethanol togive 19.1 g colorless crystals. The results of NMR and IR analysesidentified these crystals as 5-allyloxyisophthalic acid.

45.0 mmol (10 g) 5-allyloxyisophthalic acid, 150 mL methanol and 0.23 mLconcentrated hydrochloric acid were then charged to a stirrer-equippedfour-neck flask and heated under reflux for 6 hours. The methanol wasthen removed on an evaporator, the hydrochloric acid was neutralizedwith aqueous sodium bicarbonate and extraction with chloroform wascarried out. Removal of the chloroform gave 5.5 g colorless crystals.The results of nuclear magnetic resonance (NMR) and infrared absorptionspectroscopic (IR) analyses identified these crystals as dimethyl5-allyloxyisophthalate.

EXAMPLE 1

200 g hexamethylcyclotrisiloxane in tetrahydrofuran and 16.0 mL of a1.62 N hexane solution of n-butyllithium were charged to astirrer-equipped four-neck flask and were reacted for 1.5 hours at roomtemperature under a nitrogen blanket. When the extent of the reactionreached 85% (by gas chromatography), neutralization was carried out bythe addition of 38.8 mmol (3.67 ) dimethylchlorosilane with stirring.After filtration, the solvent and unreacted materials were removed bydistillation in vacuo to afford a polymer designated as HP-1.

HP-1 was identified as an organopolysiloxane with the following averageformula by means of gel permeation chromatography (GPC), nuclearmagnetic resonance absorption (NMR), infrared absorption spectroscopy(IR), and SiH group quantitation by iodometry:

    n--C.sub.4 H.sub.9 --(Me.sub.2 SiO).sub.87 SiMe.sub.2 H

This polymer's molecule weight distribution dispersity index (M_(w)/M_(n)) was 1.09 as determined by GPC.

The following were charged to a stirrer-equipped four-neck flask: 17.1mmol (112.0 g) HP-1, 17.1 mmol (4.28 g) dimethyl allyloxyisophthalate assynthesized in (Reference) Example 1, 120 g toluene, and isopropanolicchloroplatinic acid in a quantity sufficient to provide a weight ratioof 20 ppm for the quantity of platinum relative to HP-1. This wassampled after heating under reflux for 5 hours, and disappearance of theSiH peak was confirmed by IR spectroscopy. Removal of the solvent bydistillation in vacuo gave a polymer designated as FP-1.

The results of analyses by GPC, NMR, and IR identified FP-1 to be anorganopolysiloxane with the following average formula (viscosity=100.6centistokes, refractive index=1.4099): ##STR16##

EXAMPLE 2

338 mmol (100 g) octamethylcyclotetrasiloxane, 18.0 mmol (2.41 g)1,1,3,3-tetramethyldisiloxane, 0.102 g trifluoromethanesulfonic acid and0.010 g water were charged to a stirrer-equipped four-neck flask andreacted for 5 hours at 60 to 80 degrees Centigrade.

Addition of 5 g dimethylformamide for neutralization, filtration, andremoval of the volatiles by distillation in vacuo afforded a polymerdesignated as HP-2. HP-2 was identified as an organopolysiloxane havingthe following average formula by means of GPC, NMR, IR and SiH groupquantitation by iodometry:

    HMe.sub.2 SiO(Me.sub.2 SiO).sub.75 SiMe.sub.2 H

17.6 mmol (100 g) HP-2, 35.2 mmol (8.80 g) dimethyl allyloxyisophthalateas synthesized in (Reference) Example 1, 100 g toluene andplatinum/divinyltetramethyldisiloxane complex in a quantity providing 20ppm platinum based on HP-2 were then charged to a stirrer-equippedfour-neck flask. After heating under reflux for 5 hours, sampling, andexamination by IR, disappearance of the SiH peak was confirmed. Apolymer designated as FP-2 was recovered by removing the solvent bydistillation in vacuo. The results of analyses by GPC, NMR, and IRconfirmed FP-2 to be the following organopolysiloxane (viscosity=172centistokes, refractive index=1.4158): ##STR17##

EXAMPLE 3

1.76 mmol (20.0 g) organohydrogensiloxane with the formula

    Me.sub.3 SiO(MeHSiO).sub.10 (Me.sub.2 SiO).sub.150 SiMe.sub.3

17.6 mmol (4.40 g) dimethyl allyloxyisophthalate as synthesized in(Reference) Example 1, 100 g toluene andplatinum/divinyltetramethyldisiloxane complex in a quantity sufficientto give 20 ppm platinum based on the aforesaid oganohydrogensiloxanewere charged to a stirrer-equipped four-neck flask. After heating underreflux for 5 hours, sampling, and IR examination, it was found that theSiH peak had disappeared. A polymer was recovered by removal of thesolvent by distillation in vacuo. The results of analyses by GPC, NMR,and IR confirmed this polymer to be the following organopolysiloxane:

    Me.sub.3 SiO(MeB.sup.1 SiO).sub.10 (Me.sub.2 SiO).sub.150 SiMe.sub.3

in which B¹ has the structure ##STR18##

That which is claimed is:
 1. Phthalic acid ester-modifiedorganopolysiloxane characterized by the formulawherein R¹ is amonovalent hydrocarbon group, R² is a group R¹ or a group with theformula ##STR19## with the proviso that at least one of the groups R² ineach molecule is the group with the formula ##STR20## in which R³ is analkyl group, R⁴ is an alkylene group, and m is a positive integer. 2.The phthalic acid ester-modified organopolysiloxane according to claim1, wherein R¹ and R² are selected from the group consisting of methyl,ethyl and phenyl radicals.
 3. The phthalic acid ester-modifiedorganopolysiloxane according to claim 2, wherein m is 1 to 5,000.
 4. Thephthalic acid ester-modified organopolysiloxane according to claim 3,wherein R³ is selected from the group consisting of methyl, ethyl andpropyl radicals.
 5. The phthalic acid ester-modified organopolysiloxaneaccording to claim 4, wherein R⁴ is selected from the group consistingof trimethylene and tetramethylene units.
 6. The phthalic acidester-modofied organopolysiloxane according to claim 5, wherein R¹, R²and R³ are methyl radicals.